Fluid-motor



e. H. GlLMAN.

FLUID MOTOR.

APPLICATION FILED JAN-3.1916,

Patented Aug. 10, 1920.

UNITED STATES PATENT OFFICE.

" GEORGE H. GILMAN, OF CLAREMONT, NEW HAMPSHIRE, ASSIGNOR T0 SULLIVAN MACHINERY COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

morn-Moron.

Specification of Letters Patent. Patented Aug. 10; 1920,

Application filed J'anuary' 1916. Serial No. 69,937.

T 0 all whom it may concern:

Be it known that I, GEORGE H. GILMAN, a citizen of the United States, and a resident of Claremont, in the county of Sullivan and State of New Hampshire, have invented an Improvement in Fluid-Motors, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts. a

This invention pertains to fluid motors of the type known as direct acting to distinguish from fluid motors of the type primarily adapted to transform reciprocating movement into rotary movement. The fluid motor herein illustrated and described as typifying a preferred construction of one embodiment of my invention is more particularly, though not exclusively, adapted for use in percussive tools, especially in that type of percussive tool commonly known as the hammer drill.

In the drawings which show one form of my invention Figure lis a longitudinal section partly in elevation of a fluid motor;

Fig. 2 is a longitudinal section substan-' tially similar to Fig. 1 disclosing the piston at the opposite end of its stroke.

Figs. 3 and 4 are cross section views taken on section lines 3-3 and 44 respectively of Fig. 1.

The illustrative embodiment of my invention shown in the drawings, which is a preferred construction, shows the cylinder 1 presenting a rear piston chamber 2 of relatively small diameter and a front piston chamber 3 of relatively large diameter provided with a piston having a rear piston head 4 and a front )iston head 5, the said piston heads prefera 1y being of such diameter as to constitute good working fits in the front and rear piston chambers respectively. It is obvious that the words front and rear are merely relative and that the converse of the apparatus shown is equally'wlthin the scope of my invention.

Intermediate the front piston head 5 and the rear piston head 4 I preferably provide a shoulder 6 constituting one form of intermediate pressure receiving surface or area and I preferably form the piston with a groove T for purposes to be more fully described hereafter.

The fluid to operate the motor is preferably gaseous, compressed air being most satisfactory. In the embodiment of my invention illustrated, pressure fluid is admitted to the inlet passage 8 and by its pressure on the surface 9 of the valve 10 opens said valve and preferably admits fluid through the passage 11 into the rear piston chamber 2 and acting on the rear piston head 4 impels the piston forward. I prefer to utilize the intermediate pressure chamber and to this end I preferably provide a passage 13 adapted to conduct live pressure fluid to the chamber 12 where it can act on the shoulder 6 to assist in the-forward propulsion of the piston 4. i

I prefer to admit live air to the chamber 12 during only a portionof the stroke of the piston 4 and to this end I preferably locate the port 16 of the passage 13 in the cylinder wall where it can be closed by the piston 4, the admission period being determined by the length of the groove 7. In this way the expansion of the pressure fluid in the intermediate chamber 12 can be availed of during a considerableportion of the forward stroke of the piston 4. The exhaust means for the intermediate chamber is preferably piston controlled and, as shown, may comprise a port 17 opening into an exhaust passage 17' surrounding the rods 23 which, as is common in machines of this type, are used to hold the cylinder heads and chuck securely to the cylinder.

I prefer to utilize for the return of the piston 4 pressure fluid which has already been utilized during the forward stroke and to this end I may provide means for exhausting the pressure fluid from the rear piston chamber 2 into the front piston chamher 3 through the return port 18 which may be and preferably is controlled by the valve 10. The valve 10 is preferably of the pressure thrown type and may be of that species known as the differential pressure thrown type. It is preferably substantially parallel with the pistonv 4. I have found; it of marked advantage to use end seats as distinguished from circumferential seats such as are used in spool valves. The end seats are peculiarly eflicient if the valve is substantially alined with the piston, for the shock of the cylinder vibration tends to wear in the valve seats. An end seat valve is preferably provided with but two surfaces adapted to close and open ports for, if more are provided, but two will seat properly.

The system ofports disclosed permits the use of such a valve with an exhaust return of the piston.

The function of the end seat 9 of the valve 10 has already been disclosed. The opposite end seat 19 is preferably adapted to open 10 the return port 18 when the piston has nearly 7 completed its forward stroke, thereby to return the piston 4 by exhaust pressure as heretofore described.

I prefer to initiate the throw of the valve 10 by admitting pressure from the rear piston chamber 2 to the front of the valve 10 and I may perform this as shown by means of a reverse port 20 which preferably admits pressure under the front surface of the 20 valve first on a relatively small surface defined by the annular depression 21. After such initial movement pressure through the port 22 admits pressure from the rear piston chamber to act on the full area of the valve 25 surface 19 and to hold the supply conduit 8 closed while opening communication between the port 22 and the return port 18 for purposes heretofore described.

It is obvious that by corresponding 80 changes of the conduits the functions and connections of the rear piston chamber 2 and the intermediate piston chamber 12 can be reversed, that the valve 10 may be of manyforms or even dispensed with and that 85 a great number of changes by elimination, substitution, and rearrangement of elements and their functions can be made without departing from the scope of my invention, the scope of which is best defined in the ap- 40 pended claims."

What I claim as my invention and desire byLetters Patent to procure is:

1. A direct acting fluid motor having reclprocatory means presenting two pressure receiving portions adapted to receive pressure to move said reciprocatory means in one direction, conduit means for conducting pressure fluid to both of said portions, and

uid control means providing dissimultaneous cutofi's of the supply of pressure fluid to said portions during a single stroke of said reciprocatory means.

2. A direct acting fluid motor having reciprocatory means presenting two pressure receiving ortions adapted to receive live pressure uid to move said reciprocatory means in one direction, conduit means for conducting pressure fluid to both of said portions, and fluid control means providing a cutoff of the supply of pressure fluid to one of said portions early in the forward stroke of said reciprocatory means and to the other of said portions later in the stroke but prior to the return stroke of said recip- 86 rocating means.

3. A direct acting fluid motor having reciprocatory means presenting two pressure receiving portions adapted to receive live pressure fluid to move said percussive means in one direction, conduit means for conducting pressure fluid to both of said portions, and control means providing different instants of cut-off of the pressure fluid supplied to said portions and the expansive utilization of pressure fluid previously effective 76 on one of the portions to return said reciprocatory means.

4. A direct acting fluid motor having a piston providing two pressure receiving portions adapted to receive live pressure fluid 80 to move said piston in one direction, and a return pressure receiving portion adapted to receive pressure to move said piston in the opposite direction, said motor comprisingcontrolling means providing for the utilization of expansive pressure on one of the first mentioned pressure receiving portions and on said return pressure receiving portion on alternate strokes of said piston, the other of said first mentioned pressure receiving portions being subjected to live fluid pressure substantially throughout its stroke in one direction, and the remainder of this stroke being accompanied by the expansion of this last named pressure fluid.

5. A direct acting fluid motor having a plurality of pressure areas effective to receive pressure to move said piston in one direction, and admission means for admitting pressure fluid to one of said areas during substantially the entire stroke of said piston in one direction but not during the stroke of said piston in the opposite direc: tion, and to the other of said areas during a portion only of the stroke of said piston in said direction.

6. A direct acting fluid motor having a plurality of pressure-areas effective to receive pressure to move said piston in one direction, and admission means for admitting pressure fluid to one of said areas during substantially the entire stroke of said piston in one direction but not during the stroke of said piston in the opposite direction, and to the other of said areas during the first portion only of the stroke of said piston in said direction.

7. A direct acting fluid motor having a plurality of pressure areas effective to receive pressure to move said piston in one direction, admission means for admitting pressure fluid to one of said areas during substantially the entirestroke of said piston in one direction butnot during the stroke of said piston in the opposite direction, and to the other of said areas during a portion only of the stroke of said piston in said direction, and a return pressure area adapted to receive pressure fluid to move said piston in the opposite direction.

8. A direct acting fluidmotor having a plurality of pressure areas effective to receive pressure to move said piston in one direction, admission means for admitting pressure fluid to one of said areas during substantially the entire stroke of said piston in one direction but not during the stroke of said piston in the opposite direction, and to the other of said areas during a portion only of the stroke of said piston in said direction, and a return pressure area adapted to receive expansive pressure fluid to move said piston in the opposite direction.

9. A direct acting fluid motor having a plurality of pressure areas effective to receive pressure to move said piston in one direction, admission 'means for admitting pressure fluid to one of said areas during substantially the entire stroke of said piston in one direction but not during the stroke of said piston in-ithe opposite direction, and to the other of said areas during a portion only of the stroke of said piston in said direction, a return pressure area effective to receive expansive pressure fluid to move said piston in the opposite direction and conduit meansfor conducting said expansivepressure fluid from the pressure fluid chamber of one of said pluralityof pressure areas to said return pressure area. i

10. A direct acting fluid motor comprising, in combination, reciprocating means having-two pressure receiving areas adapted to receive pressure to move said reciprocating means in the same direction, valve means for controlling the admission of pressure fluid to bothof said areas, and'supplementary cutoff means independent of said valve means and dependent on movement of said reciprocating means to cutofl the supply of pressure fluid to one of said areas.

11. A direct acting fluid motor comprising, in combination, reciprocating means having two pressure receiving areas adapted to receive pressure to move said reciprocating means in the same direction, valve means for controllingthe admission of pressure fluid to both of said areas, supplementary cut off means independent of said valve means and dependent on movement of said reciprocating means to cutofit' the supply of pressure fluid to one of said areas, a return pressure receiving surface provided by said reciprocating means and conduit means for conducting expansive pressure fluid previously effective on the other of said areas to said return pressure receiving surface to effect return movement of said reciprocating means.

12. A direct'acting fluid motor comprising, in combination, reciprocatin; means having two pressure receiving areas adapted to receive pressure to move said reciprocating means in the same direction, valve means for controlling the admission of pressure fluid to both of said areas, supplementary cutofl means independent of said valvemeans and dependent on movement of said reciprocating means to cut ofl the supply of pressure fluid to one of said areas, a return pressure receiving surface provided by said reciprocating means,'and conduit means controlled by said valve means for conducting expansive pressure fluid previously effective on the other of said areas to said return pressure receiving surface to actuate return movement of said reciprocating means. v

13. A direct actin pressure fluid motor comprising a piston aving two areas effective to receive pressure fluid to move said piston in the same direction and a pressure receiving area effective to receive pressure fluid to move said piston in the opposite direction, a valve having a single port for admitting pressure fluid to said two first,

named areas, and conduit means for conducting pressure fluid from one of said first named areas to said last named area to actuate the return of said piston.

14. A direct acting pressure fluid motor comprising a pistonhaving two areas efl'ective to receive pressure fluid to move said tive to receive pressure fluid to move said piston in the same direction and a pressure receiving area effective to receive pressure fluid to move said piston in the opposite direction, a valve having a single port for admitting pressure fluid to said two first named areas, and conduit means controlled by said valve for conducting pressure fluid from one of said first named areas to said last named area to actuate the return of said piston. Y

16. A direct acting pressure fluid motor comprising a piston having two areas efiective to receive pressure fluid to move said piston in the same direction and a pressure receiving area effective to receive pressure fluid to move said piston in the opposite direction, a double end seat plate valve havin a single port for admittlng pressure fiui to said two first named areas, and conduit means for conducting ressure fluid from one of said first name areas to said last named area to actuate the return of said piston.

17. A direct acting pressure fluid motor comprising a piston having a pressure receiving area adapted to receive pressure fluid to move said piston in one direction, a relatively larger pressure receiving area adapted to receive pressur tomove said piston in the opposite direc ion, and a valve having two alternately effective end seats, one seat controllin the admission of pressure fluid to the flrst named ressure receivin area to actuate said piston in one direction and the other seat controlling exhaust of motive fluid from said first named area into a conduit adapted to conduct said exhaust fluid to said relatively larger pressure receiving area to actuate said piston in the opposite direction.

' 18. A direct acting pressure fluid motor having a piston presenting two pressure receiving areas adapted to receive pressure to move said piston in one direction, a valve having a single port for admitting pressure to both of said areas and a port for control- I ling the exhaust of one of said areas, and

piston controlled exhaust means for the other area.

'19. A direct acting pressure fluid motor having a piston presenting two pressure receiving areas adapted to receive pressure to move said piston in one direction, an end seat plate valve having a single port for admittin pressure to both of said areas and a port for controlling the exhaust of one of said areas, and piston controlled exhaust means for the other area.

20. A direct acting pressure fluid motor having a piston presenting two pressure receiving areas adapted to receive pressure to move said piston in one direction and a larger pressure receiving area adapted to receive pressure to move said piston in the opposite direction, a valve having a single port for admitting pressure to both of said two areas and a port for controlling the exhaust of one of said two areas, piston controlled exhaust means for the other area, and controlling conduit means for conductmg exhaust fluid to said larger pressure receiving area.

21. A direct acting pressure fluid motor comprising, in combination, a piston having two live pressure fluid areas effective to receive pressure to move said piston in one direction, a valve controlling the admission of pressure fluid to said two pressure areas, and supplementary valve means dependent on movement of said piston to supplement control of said admission to one of said areas.

' 22. A direct acting pressure fluid motor comprising a piston providing two pressure receiving portions adapted to receive pressure to move said piston in one direction and a return pressure receiving portion of greater area than either of the two first mentioned pressure receiving portions, in

combination with a valve controlled by the position of one of said first mentioned pressure receiving portions for controlling the admission, cut-off, and exhaust for one of said first mentioned pressure receiving portions and the admission of said exhaust to said return pressure areceiving portion, and piston controlled cut-off means for the other of said first named pressure receiving portions.

23. A direct acting pressure fluid motor comprising a piston providing two pressure receiving portions adapted to receive pressure to move said piston in one direction and a return pressure receiving portion of greater area than either of the two first mentioned pressure receiving portions, in combination with a valve controlling the admission and exhaust for one of said first mentioned pressure receiving portions and the admission of said exhaust to said return pressure receiving portion, and piston c011- trolled cut-ofl means for the other of said first named pressure receiving portions.

24. A direct acting pressure fluid motor comprising a piston, providing two pressure receiving portions adapted to receive pressure to move said piston in one direction, and a return pressure receiving portion of greater area than either of the two first mentioned pressure receiving portions, in combination with a valve controlling the admission, cut ofl', and exhaust of one of said first mentioned pressure receiving portions and the admission of said exhaust to said return pressure receiving portion, and cut-ofl' and exhaust means, for the other of said first named pressure receiving portions overrun by the piston,

25. A direct acting pressure fluid motor comprising a piston provided with two pressure receiving portions adapted to receive pressure to move said piston in one direction and a return pressure receiving portion of greater area than either of said first mentioned pressure receiving portions, in combination with a valve controlling admission, cut-ofl", and exhaust for one of said first mentioned pressurereceiving portions and admission of said exhaust to said return pressure receiving portion, piston controlled cut-ofl' means distinct from said valve for the other of said first mentioned pressure receiving portions, and piston controlled exhaust means for said return pressure receiving portion.

26. A direct acting pressure fluid motor comprising a piston providing two pressure receiving portions adapted to receive pressure to move said piston in one direction and a return pressure receiving portion of greater area than either of the two first mentioned pressure receiving portions, inc'ombination with a valve movable to control the admission, cut off, and exhaust for one of said first mentioned pressure receiving portions and the admission of said exhaust to said return pressure receiving portion, exhaust means for the other of said first named pressure receiving portions, and means controlled by the piston whereby cut-01f therefor is effected prior to movement of the valve to effect cut-off for said first mentioned pressure receiving portion.

27. A direct acting pressure fluid motor comprising a piston providing two pressure receiving portions adapted to receive pressure to move said piston in one direction and a return pressure receiving portion of greater area than either of the two first mentioned pressure receiving portions, in combination with a valye controlling the admission, cut off, and exhaust for one of said first mentioned pressure receiving portions and the-admission of said exhaust to said return pressure receiving portion, piston overrun cut-off and exhaust means for the other of said first named pressure receiving portions, and piston controlled exhaust means for said return pressure receiving portion.

28. In a hammer drill, a piston, a cylinder presenting front and rear piston chambers, a valve chamber communicating with said rear piston chamber and, by a passage coaxial substantially throughout its length with itself, with the front piston chamber,

' and a valve in said chamber of two diameters presenting seats on its opposite ends, one of said seats bein adapted to control the air admitted to sai rear' piston chamber and the other seat being adapted to control the exhaust therefrom to said front piston chamber through said coaxial port.

29. In a hammer drill, a piston, a cylinder presenting a rear piston chamber; and a valve of two diameters presenting seats on its opposite ends for controlling theair admitted to and exhausted from said rear pisder presenting a rear piston chamber and a front piston chamber, and an imperforate valve presenting a seat engaging surface of different diameter on each end thereof for controlling pressure fluid admitted to or exhausted from said rear piston chamber and pressure fluid supplied to said front end, the surface of larger diameter having a portion always in communication with said front piston chamber and a portion intermittently exposed to pressure in said rear piston chamber.

32. A "hammer drill comprising in combination a cylinder having front and rearpiston chambers of different diameters, a

piston having pressure surfaces of different. areas, conduit, means for conducting pres-' sure fluid from said rear piston chamber to said front piston chamber, a valve in said conduit means and substantially parallel with the piston and presenting opposite pressure surfaces of different areas, the smaller of said surfaces being constantly acted on by the live fluid and the larger of said surfaces having a portion thereof al ways in communication with the front piston chamber.

In a direct actingfluid motor, a cylinder, a piston having two heads and a groove intermediate said heads adjacent the forward head, and a valve for controlling admission of motive fluid to the opposite ends of said cylinder, the supply of motive fluid to one side of one of said piston heads being controlled by the position of said groove.

34. In a direct acting fluid motor, a cylinder, a piston having two heads and a groove intermediate said heads, conduit means adapted to cooperate with said groove to admit pressure fluid to one side of one of said heads, and a valve controlling admission of motive fluid to the opposite ends of said cylinder, the position'of said valve being controlled by the position of one of said heads.

35. In a direct acting fluid motor, a cylinder, a piston having two heads and a groove intermediate said heads, and a valve controlling admission of motive fluid to the opposite ends of said cylinder, the supply of motive fluid to one side of oneof said heads being controlled by the position of said groove, and the position of said valve of said heads.

36. In a direct acting fluid motor, a cylinder, a valve, and a piston having two heads and a groove intermediate said heads, said valve and groove cooperating to control the admission of motive fluid to the several parts of said cylinder at suitable times to cause reciprocation of said piston therein, and the position of said valve being iio being controlled by the position of the other combination, a drill cylinder, its piston, cyl- In testimony whereof I have signed my inder closure means, a plurality of tension name to this specification in the presence of members for holding said closure means in two subscribing witnesses.

proper relation to the cylinder, apertures GEORGE H. GILMAN. 5 surrounding said tension members, and ex- Witnessesz r haust means for conducting exhaust air DOUGLAS M. BARCLAY,

I from said cylinder into said apertures WILLIAM BARCLAY} 

